Golfing Machine Science.
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Brian Manzella
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Needed a little clean up, and yours was the baby the went out with the bathwater...
Axel_WIngert
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If the ball is travels with the clubface for a 3/4 of an inch (good assumption- the ball is about halvecompressed on impactpictures) and the golfer is about 0,7 yards away from the ball (just an instant guess from me) the angle can be calculated as
arcsin(or "sin high-1"){3/4 inch / 0,7 yards}.
3/4 inch should be about 0,03 yards...
arcsin( 0,03/0,7)= 2,46 degrees
...looks like 3 degrees aren't too far away
arcsin(or "sin high-1"){3/4 inch / 0,7 yards}.
3/4 inch should be about 0,03 yards...
arcsin( 0,03/0,7)= 2,46 degrees
...looks like 3 degrees aren't too far away
Brian Manzella
Administrator
Thanks Axel!
bts
New
This is how I check the clubface "openness" horizontally and vertically (effective loft) at impact:
Mark a cross with Sharpei on the ball and place it on the tee, so that the center of the cross is at the back equator in-line with the target line. Hit the ball with the clubface taped with impact tape and check the distance of the center of the cross (printed on the clubface during impact) to that of the ball mark.
The further the cross away from the center of the ball mark, the more clubface angle at impact.
934
Axel::
I think you may be calculating the wrong angle. The clubhead must rotate the 3º around the Sweet Spot (2-F) to square up according to TGM. So the picture shown at the beginning of this thread is flawed or misleading because it shows rotation around the shaft. Not according to Homer !!!
The 0.7 yards, or 25 inches may be the distance on the ground but the clubface does not rotate around a center that is 25 inches away.
You must use the radius of the Club-Left Arm Assembly from Left shoulder to the Sweet Spot according to Homer in Chapter 2. This is approximately 75 inches with a driver and down to 65 inches with a wedge. So the geometry of the Impact is measured with these numbers and not your 0.7 yards.
The angular sweep of the arm and club is only about 1/2 degree from initial Impact to Separation. I posted more detailed calculations on Homer's horrendously out-of-scale sketches on page 17 of TGM, but Brian deleted them for some reason.
Why bother posting here when correct scientific fact is suppressed. If you believe in Homer and God, scientific truth doesn't matter.
Brian Manzella
Administrator
Horton. Welcome back.
My pictures defy all of this over analysis.
If the clubface opens to the path, and it will with ZERO manipulation, it is about 3 degrees.
I came up with the drawing of the path from an over-head picture of Tom Bartlett:
http://homepage.mac.com/brianmanzella/.Movies/bartlett3.mov
The clubface simply stayed 'square' to the path.
A very inetersting side-bar is this: In 1984, my first year of teaching for a living, I worked at a shop that was very high-tech for its day. We had a very expensive machine developed by a big company in Japan, that measured all sorts of things INCLUDING where the clubface was at IMPACT.
IMPACT.
I was very excited. So I practiced for three days inddors on the 'machine' and got to the point where I could get the clubface DEAD SQUARE at impact 99% of the time.
I was ready to quit my job and go on the TOUR.
The fourth day I went tot the range to hit balls before my lessons, so I could see how great I was...
...ooops!
Guess where EVERY shot went?
Not straight!
Dead left!
So....
each day I practiced a different degree of open-ness to see which one produced straight balls...
3 degrees open.
(Of course this was not a scientific test.....but....)
My pictures defy all of this over analysis.
If the clubface opens to the path, and it will with ZERO manipulation, it is about 3 degrees.
I came up with the drawing of the path from an over-head picture of Tom Bartlett:
http://homepage.mac.com/brianmanzella/.Movies/bartlett3.mov
The clubface simply stayed 'square' to the path.
A very inetersting side-bar is this: In 1984, my first year of teaching for a living, I worked at a shop that was very high-tech for its day. We had a very expensive machine developed by a big company in Japan, that measured all sorts of things INCLUDING where the clubface was at IMPACT.
IMPACT.
I was very excited. So I practiced for three days inddors on the 'machine' and got to the point where I could get the clubface DEAD SQUARE at impact 99% of the time.
I was ready to quit my job and go on the TOUR.
The fourth day I went tot the range to hit balls before my lessons, so I could see how great I was...
...ooops!
Guess where EVERY shot went?
Not straight!
Dead left!
So....
each day I practiced a different degree of open-ness to see which one produced straight balls...
3 degrees open.
(Of course this was not a scientific test.....but....)
brainman .... many strange things happen through final Release and the Impact Event. I would hazard to say that Impact Event may be different for each golfer because everybody's Release is slightly different due to Anatomy. Because we are dealing with very minute dimensions at very high speeds, it may be nigh impossible to generalize.
In the Budney and Bellow study of grip pressure measurement, patterns did emerge but they vary significantly between different levels of golfers. In all cases, grip pressure increased just prior to Impact when final Release action was applied through Right Hand Thrust, but then there was a huge momentary drop in grip pressure at Impact, and in one case for a pro golfer, the grip pressure dipped to zero before being regripped! This is easily explainable dynamically, but difficult for subjective golfers to sense or accept. The B & B study is in Science and Golf I.
You can visualize and assume you are striking the ball on the quadrant, but in real fact the dimensions you are talking about are so miniscule, that they are overwhelmed by the visco-elastic nature of Impact upon the ball. Yes you can attempt to hit down and out, but as you can see from the Bartlett mov, it is indistinguishable. When unsubstantiated delusion becomes the accepted mantra then facts are discarded to fit the theory.
What is wrong with just "looking at" stop-frame photos, is that the dynamic</u> event is not fully appreciated. Unscientific laymen such as you and Homer look at a picture and say "see what it shows us therefore .....". What you need before you can draw any conclusion from positional pictures of the golfswing is factual calculations to verify your conclusions. Going from a picture to a conclusion, as Homer has done in TGM, is entirely unscientific. Homer may have guessed right in some instances, but without verifiable proof in the form of definitive calculated results, your conclusions are only subjective anecdotal experiences.
As for your hitting the ball to the left with a square clubface, that may also be due to your coming over the top and hitting from outside in. Simple assumption may be quite reasonable even though you may not like it. Another Impact factor may be the "kickback effect" determined in the Masuda et al study in Science & Golf II. When the clubhead mass reacts to ball mass in microsecond vibrational events, things happen that are quite unexpected and may very well explain why you hit the ball left with a square clubface.
I invite you to broaden your perspective as to what may actually happen during the Impact Event with new scientific discoveries so that you are not stuck with Homer's speculations thus leaving you trying to rescue TGM in it's stagnant state. Just because your teaching or playing results are good, you just cannot claim that TGM is correct in it's so-called science. When unscientific people try to proclaim something is correct based on a science they do not understand that makes me dubious, very dubious ... can you blame me?
All legitimate science required objective calculated results to prove it's theory. No numbers, no science, it's just that simple. Do you see any numbers in TGM? A real engineer would have provided us with numerical proofs and not just verbal guessing. Sorry but that's how I see it and I know I am correct .. scientifically thinking. Again, great golfswing method, lousy science and that's why TGM has never been subjected to scientific examination.
In the Budney and Bellow study of grip pressure measurement, patterns did emerge but they vary significantly between different levels of golfers. In all cases, grip pressure increased just prior to Impact when final Release action was applied through Right Hand Thrust, but then there was a huge momentary drop in grip pressure at Impact, and in one case for a pro golfer, the grip pressure dipped to zero before being regripped! This is easily explainable dynamically, but difficult for subjective golfers to sense or accept. The B & B study is in Science and Golf I.
You can visualize and assume you are striking the ball on the quadrant, but in real fact the dimensions you are talking about are so miniscule, that they are overwhelmed by the visco-elastic nature of Impact upon the ball. Yes you can attempt to hit down and out, but as you can see from the Bartlett mov, it is indistinguishable. When unsubstantiated delusion becomes the accepted mantra then facts are discarded to fit the theory.
What is wrong with just "looking at" stop-frame photos, is that the dynamic</u> event is not fully appreciated. Unscientific laymen such as you and Homer look at a picture and say "see what it shows us therefore .....". What you need before you can draw any conclusion from positional pictures of the golfswing is factual calculations to verify your conclusions. Going from a picture to a conclusion, as Homer has done in TGM, is entirely unscientific. Homer may have guessed right in some instances, but without verifiable proof in the form of definitive calculated results, your conclusions are only subjective anecdotal experiences.
As for your hitting the ball to the left with a square clubface, that may also be due to your coming over the top and hitting from outside in. Simple assumption may be quite reasonable even though you may not like it. Another Impact factor may be the "kickback effect" determined in the Masuda et al study in Science & Golf II. When the clubhead mass reacts to ball mass in microsecond vibrational events, things happen that are quite unexpected and may very well explain why you hit the ball left with a square clubface.
I invite you to broaden your perspective as to what may actually happen during the Impact Event with new scientific discoveries so that you are not stuck with Homer's speculations thus leaving you trying to rescue TGM in it's stagnant state. Just because your teaching or playing results are good, you just cannot claim that TGM is correct in it's so-called science. When unscientific people try to proclaim something is correct based on a science they do not understand that makes me dubious, very dubious ... can you blame me?
All legitimate science required objective calculated results to prove it's theory. No numbers, no science, it's just that simple. Do you see any numbers in TGM? A real engineer would have provided us with numerical proofs and not just verbal guessing. Sorry but that's how I see it and I know I am correct .. scientifically thinking. Again, great golfswing method, lousy science and that's why TGM has never been subjected to scientific examination.
With all due respect, I beg to differ.
This is pretty much the definition of science.
1. You start w/ a (mental) model saying square at impact is good.
2. Thanks to Japanese high tech measuring device, you can train yourself to produce different angles.
3. By conducting a series of experiments, you firstly disprove the original model and secondly prove that 3* open is good.
This is what science really is all about - making meaningfull and provable hypothesis about universe - and then testing them untill they break.
Any critique should be directed to your experiment protocol. If you had measured the impact angle at real time, you would be home free.
It is cool to hear you did away w/ the square-at-impact paradigm - I know using a word paradigm is a bit Wagnerian - allready at 1984.
1984 - I'm getting funny Orwellian flashbacks.
Vaako
golf_sceptic
New
I'm late on the scene I know, but I'm very impressed with Brian's pictures of impact. My background is in Applied Mathematics and Physics. I don't know what Homer's book says, but I can tell you that my analysis agrees with Axel, and Brian's methodology with the Japanese measuring device is spot on.
Now that's off my chest, Brian do you have any analysis of what happens when the clubhead path through impact is not aligned with the club face. I'm particularly interested in the direction the ball leaves the clubface. I've heard three versions. One that it is almost 100% clubface direction. A second that it is about 83% clubface 17% path (Pelz) and a third "Search for the perfect swing" that says is is about 2/3 clubface 1/3 path.
Now that's off my chest, Brian do you have any analysis of what happens when the clubhead path through impact is not aligned with the club face. I'm particularly interested in the direction the ball leaves the clubface. I've heard three versions. One that it is almost 100% clubface direction. A second that it is about 83% clubface 17% path (Pelz) and a third "Search for the perfect swing" that says is is about 2/3 clubface 1/3 path.
Axel_WIngert
New
I'm particularly interested in the direction the ball leaves the clubface. I've heard three versions. One that it is almost 100% clubface direction. A second that it is about 83% clubface 17% path (Pelz) and a third "Search for the perfect swing" that says is is about 2/3 clubface 1/3 path.
I think it depends on impact speed
I think it depends on impact speed
golf_sceptic
New
Thanks Axel, that would make sense.
What would it be for a full shot with a 5-iron or driver.
What would it be for a full shot with a 5-iron or driver.
golf_sceptic
New
Whilst I think of it, a calculation was presented here saying that the 3* to square rotation would be 1000 rpm.
---I stand corrected. The 1000RPM figure is correct---
My mistake below is that it is 16.7 Revs Per Second
which is 1000 RPM.
------------------------------------------------------
The arithmetic is this
If the clubhead rotates 3* in 0.5 ms, that is 6000* per second.
Converting to RPM is 6000/360 = 16.7 RPM
I don't know whether the 0.5ms figure is right (it sounds close)
or what sidespin it takes to move a ball 5 yards in flight, but
even is all of this rotation is transferred to the ball I'd imagine
that the effect would be pretty small.
Another question was in regards to an error of say 1* at impact.
A useful rule of thumb is that 1* is 1 yard per 60 yards, so for
a 180 yard shot a 1* error will produce about 3 yards off target.
To me, that sounds very consistent with Brian's experience with
the square clubface at impact making every shot go left.
These calculations don't take into account any sidespin caused
by the clubface not looking in the same direction as the clubhead
is moving. If anybody's got any data on that I'd be very interested.
---I stand corrected. The 1000RPM figure is correct---
My mistake below is that it is 16.7 Revs Per Second
which is 1000 RPM.
------------------------------------------------------
The arithmetic is this
If the clubhead rotates 3* in 0.5 ms, that is 6000* per second.
Converting to RPM is 6000/360 = 16.7 RPM
I don't know whether the 0.5ms figure is right (it sounds close)
or what sidespin it takes to move a ball 5 yards in flight, but
even is all of this rotation is transferred to the ball I'd imagine
that the effect would be pretty small.
Another question was in regards to an error of say 1* at impact.
A useful rule of thumb is that 1* is 1 yard per 60 yards, so for
a 180 yard shot a 1* error will produce about 3 yards off target.
To me, that sounds very consistent with Brian's experience with
the square clubface at impact making every shot go left.
These calculations don't take into account any sidespin caused
by the clubface not looking in the same direction as the clubhead
is moving. If anybody's got any data on that I'd be very interested.
Brian Manzella
Administrator
Yes, I do have those numbers....
Will post them tommorrow.
Will post them tommorrow.
golf_sceptic
New
As I said above, my apologies for the bogus calculation.
The questions now are what RPM produces what curve, and
how much of the clubhead rotation at impact is transferred
to the ball.
Brian's numbers will give us the answers.
The questions now are what RPM produces what curve, and
how much of the clubhead rotation at impact is transferred
to the ball.
Brian's numbers will give us the answers.
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